"He did many good works. He was always a soft touch," Ishmael Reed said.

One of his most controversial international missions was his trip to Iraq in 1990. He met with dictator Saddam Hussein and pressed him to release 15 American hostages taken during the first Gulf War. It was a mission that was first criticized, but eventually praised because they were released.

"President Bush would eventually award him the Medal Of Freedom," Ishmael said.

Ali was one of the most famous Muslims in the world and his stardom had real influence.

Bay Area native and Washington Post correspondent Jason Rezaian told CNN that after Ali made a personal appeal to Iran to release him last year. He noticed his prison guards began to treat him differently.

"They started treating me in a better way. I think it brought some doubt to them about the charges against me," Rezaian said.

Rezaian had been held on espionage charges by Iran since 2014. He was released this January.